高级迭代重建在双低肺动脉CT成像的应用价值  

Application of Advanced Iterative Reconstruction in Double-low Pulmonary Artery CT Angiography

作　　者：曹治婷[1] 刘铁军[1] 廖立 陈刚[1] 邹莹[1] 廖玉荣[1] 曹治柳[2] CAO Zhi-ting;LIU Tie-jun;LIAO Li;CHEN Gang;ZOU Ying;LIAO Yu-rong;CAO Zhi-liu

机构地区：[1]柳州市人民医院放射科 [2]广西医科大学外国语学院

出　　处：《中国医学计算机成像杂志》2019年第2期192-196,共5页Chinese Computed Medical Imaging

基　　金：广西省卫计委自筹经费科研课题Z20170651~~

摘　　要：目的:探讨迭代重建技术(i Dose4)在低辐射剂量和低对比剂碘量("双低技术")肺动脉CT成像的应用价值。方法:将60例体质量指数正常疑似肺动脉栓塞行CTPA检查患者随机分常规剂量A组、低剂量B组两组,每组各30例。A组采用120kV、200mAs,370mgI/ml对比剂60ml,对原始数据进行滤波反投影(FBP)重建;B组采用80kV、固定管电流80mAs,300mgI/ml对比剂35ml,对原始数据分别进行滤波反投影(FBP)、迭代iDose4 3级和iDose4 6级重建,依次标记为B1、B2、B3组。记录各组的CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP),计算有效剂量(ED);测量背景噪声(BN)、肺动脉强化平均CT值(SIvessel),计算信噪比(SNR)、对比噪声比(CNR)。比较各组的辐射剂量及图像质量,进行统计学分析。结果:B组的有效剂量(ED)(0.88±0.99)mSv相较A组(3.81±0.40)mSv降低约76.9%(t=31.6,P <0.05),总碘量22.2g较A组10.5g降低约52.7%。B2组的SNR、CNR及主观评分与A组比较均没有统计学意义(P> 0.05);B3组的SNR、CNR均高于A组(P <0.05),主观评分与A组没有统计学意义(P> 0.05);B1组的SNR、CNR、主观评分均低于A组(P <0.05)。结论:i Dose4迭代重建技术不但有效减少图像噪声,提升图像分辨率,不改变图像质量,而且i Dose4级数越高在同等条件下处理效果更好。在双低肺动脉CT成像中运用i Dose4 6级重建效果为更佳。。Purpose: To explore the value of applying low radiation dose and low contrast-agent of iodine(doublelow technique) with iterative reconstruction technique in CT pulmonary angiography(CTPA). Methods: Sixty patients with normal body mass index and suspected with pulmonary embolism were randomly divided into 2 groups. In the conventional dose group(Group A), 30 cases were examined with protocol of 120 kV, 200 mAs and370 mgI/ml contrast agent 60 ml, with filtering inverse projection(FBP) for image reconstruction. In Group B, 30 cases were examined with protocol of fixed tube current 80 mAs and 80 kVs, 35 ml contrast-agent, with filtering inverse projection(FBP), third level iterative reconstruction iDose4 and sixth level iterative reconstruction iDose4 for imaging reconstruction, which were labeled as B1, B2 and B3. CT dose index volume(CTDIvol), DLP, effective dose(ED), BN, SIvessel, SNR and CNR in each group were recorded and compared. Results: The ED of mSv in group B(0.88±0.99) was decreased by 76.9%(t=31.6,P<0.05) compared with mSv in group A(3.81±0.40) and the amount of total iodine in group B was 22.2 g, decreased by 52.7% compared with the number of 10.5 g in group A.There were no statistical significant differences between B2 and group A in terms of SNR, CNR and subjective scores.The SNR and CNR in B3 were higher than those in group A(P<0.05) and no statistical significant differences existed in the subjective scores between B3 and group A(P>0.05). The SNR, CNR and subjective scores in B1 were lower than those in group A(P<0.05). Conclusion: The iDose4 iterative reconstruction technology can effectively reduce image noise, improve image resolution, and do not change image quality. The higher the iDose4 level, the better the processing under the same conditions. The application of sixth level iDose4 for iterative reconstruction in CTPA works better.

关 键 词：CT肺动脉成像 体层摄影术 辐射剂量 固定管电流 迭代重建 

分 类 号：R445.3[医药卫生—影像医学与核医学]